In general, for manufacturing a prototype product having a three-dimensional shape, a mock-up manufacturing method which is manually performed based on a drawing, and a manufacturing method through CNC milling have been widely used.
However, since the mock-up manufacturing method is manually performed, it is difficult to accurately perform a numeric control, and also it takes a lot of time. In the case of the manufacturing method through the CNC milling, it is possible to accurately perform the numeric control, but it is difficult to perform a machining operation due to tool interference.
Therefore, recently, a new method referred to as a 3D printing method in which a designer of a product generates three-dimensional modeling data using a CAD or a CAM and a prototype product having a three-dimensional shape is manufactured using the generated data, has been proposed. Such a 3D printer is being used in various fields such as an industrial field, a field of life, and a medical field.
The 3D printer is a manufacturing apparatus which manufactures an object by outputting continuous layers of a material, like in a 2D printer, and then stacking the layers. Since the 3D printer may rapidly manufacture the object based on digitized drawing information, it is mainly used to manufacture a prototype sample or the like.
A product forming method of the 3D printer includes a method in which a laser beam is applied to a photo-curing material, and then a portion to which the laser beam is applied is machined as an object, a method in which a forming material is cut, and a method (a FDM method) in which a thermoplastic filament is melded and stacked.
Since a 3D printer using the method in which the thermoplastic filament is melded and stacked, among the above-described methods, has a lower unit cost of production than 3D printers using other methods, thus it is being popularized for domestic use, industrial use, or the like.
In Korean Patent Publication No. 10-2014-0121034, there is disclosed a 3D printer in which a flexible shaft connected with a motor to transmit power, a feeder roller rotatably connected to the flexible shaft, and a hot end nozzle are included. For this hot end nozzle, a filament is supplied by rotation of the feeder roller and the supplied filament is melted and then sprayed, and the filament is uniformly, stably and rapidly supplied to the hot end nozzle.
Here, in the 3D printer disclosed in the above-described patent document, a user should insert the filament into an extruder, i.e., into the hot end nozzle through the feeder roller in the early stage of use, and such a manual supply method of the filament has the following problems.
First, since an insertion hole of the extruder into which the filament is inserted is very narrow, and also the filament is generally wound and thus has a curved shape, it is not easy to accurately insert the filament into the nozzle via the feeder roller.
Also, when the filament is formed of a ABS plastic material containing harmful ingredients, the user may be exposed to the harmful ingredients, and the filament may also be contaminated due to contact with the user.
And the filament inserted into the extruder may be fixed in the extruder after a printing operation, and thus may cause a clogging phenomenon. In this case, it is very difficult to discharge the filament fixed in the extruder.